Oxo process using ligands of the tropolone group

ABSTRACT

1. IN THE REACTION OF A C2-C20 OLEFINICALLY UNSATURATED HYDROCARBON WITH CARBON OONOXIDE AND HYDROGEN WHEREIN THE REACTION IS CATALYZED BY A COBALT CARBONYL COMPLEX COMPOUND, WHICH IS FREE OF COBALT-PHOSPHORUS BONDS AND OF METAL-METAL BONDS OTHER THAN COBALT-COBALT BONDS, THE IMPROVEMENT WHICH COMPRISES CARRYING OUT THE REACTION AT A TEMPERATURE IN THE RANGE FROM 75*C. TO 225*C. AND ABOUT 50 TO 5000 P.S.I.G. AND WITH THE REACTANTS IN CONTACT WITH FROM 0.001 TO 1 MOLE PER GRAM OF COBALT OF AN OXYGEN-DENTATED CHELATION LIGNAD OF THE FORMULA   1-(O=),2-(R-O-),(R)N-2,4,6-CYCLOHEPTATRIENE   WHEREIN THE R GROUPS ARETHE SAME OR DIFFERENT AND ARE HYDROGEN OR AN ALKYL GROUP HAVING A CARBON ATOM CONTENT IN THE RANGE 1 TO 50 AND WHEREIN N IS 5, THEREBY INHIBITING THE DISSOCIATION OF SAID CATALYST TO METALLIC COBALT AND RESIDUE WHICH OCCURS IN THE ABSENCE OF THE LIGAND.

United States Patent 3,839,471 0X0 PROCESS USING LIGANDS OF THETROPOLONE GROUP John B. Wilkes, Richmond, Califi, assignor to ChevronResearch Company, San Francisco, Calif.

No Drawing. Original application Mar. 20, 1969, Ser. No. 809,028, newPatent No. 3,647,842. Divided and this application June 14, 1971, Ser.No. 153,054

Int. Cl. C07c 27/20, 29/16 US. Cl. 260-632 HF 8 Claims ABSTRACT OF THEDISCLOSURE At a temperature in the range 100 C. to 225 C. thedestructive dissociation of cobalt carbonyl compounds to cobalt metaland residue is inhibited by the action of oxygen-dentated chelationligands.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisionof copending application Ser. No. 809,028, filed Mar. 20, 1969, and nowUS. Pat. 3,647,842.

FIELD OF INVENTION BACKGROUND OF INVENTION Cobalt carbonyl compoundsincluding dicobalt octacarbonyl, cobalt hydrocarbonyl etc. as such or inmodified forms are known for their use as catalysts for a variety ofreactions relating to olefinic unsaturated organic compounds includingthe hydroformylation (oxonation) of olefins, isomerization of olefins,carbonylation of amines and aromatic nitriles, hydrosilation of olefinsand the like. These catalyst complexes are subject to seriouslimitations in that unless carbon monoxide pressures in excess ofequilibrium values are maintained in their presence, these compoundsdestructively dissociate into cobalt metal and residue. Catalyticactivity is thus lost and cobalt metal is plated-out on reactor wallsand associated transfer piping. From time to time the accumulated metalmust be removed by a suitable means, usually by the use of aqueousnitric acid or a similar undesirably corrosive and inconvenient agent.

It is therefore an object of the present invention to provide a methodfor the stabilization of cobalt carbonyl complex compounds, therebysubstantially reducing cobalt metal deposition on the surfaces ofreaction vessels and associated lines.

Another object of the invention is to provide a method for thestabilization of cobalt carbonyl complex compounds thereby permittingtheir effective use as catalysts at lower carbon monoxide pressures andat higher temperatures than may be satisfactorily employed under con- 1ventional hydroformylation reaction conditions.

Another object of the invention is to provide a method to inhibit theplating-out of cobalt metal on the surfaces of a system containingcobalt carbonyl complex compounds from the destructive dissociation ofcobalt carbonyl complex compounds.

3,839,471 Patented Oct. 1, 1974 Still another objective is the provisionof an improved hydroformylation process in which alcohol is produced ina single stage process by the reaction of an olefinic hydrocarbon withcarbon monoxide and hydrogen in the presence of a cobalt carbonylcatalyst and facilitated by added oxygen-dentated chelation ligands.Other objects and advantages of the present invention will becomeapparent from the ensuing detailed description thereof.

In accordance with the present invention the stability of cobaltcarbonyl complex compounds in a system in the presence of carbonmonoxide gas is improved at a temperature in the range of from about C.to 225 C. by the addition of an oxygen-dentated chelation ligand havinga substantial standard cobalt-ligand association constant.

In a more particular aspect of the invention organic compoundscontaining olefinic unsaturation are converted to saturated alcoholsand/or aldehydes having at least one more carbon atom than the precursorolefinic compounds by the reaction of the compound in the liquid phasewith carbon monoxide and hydrogen in a reaction system in which theabove described stabilized cobalt carbonyl complex compounds areemployed as the catalyst. In a corollary aspect of the invention theplatingout of cobalt metal on the surfaces of systems containing theaforementioned cobalt carbonyls is inhibited by the addition of theabove described ligands.

Surprisingly, the presence of the subject ligands markedly inhibitsdestructive dissociation of cobalt carbonyl compounds to metal. In theirpresence, carbon monoxide pressures below conventional equilibriumpressures can be employed with little or no deposition of cobalt metal.Thus, in the presence of the subject ligands operation at elevatedtemperatures is made possible at considerably lower pressures than areotherwise required, and this permits substantial economies of plantconstruction and operation. A further advantage of the subject processover the art accrues in that in conventional hydroformylation practice,the hydrogenation of aldehyde to alcohol is inhibited by the necessarilyhigh carbon monoxide partial pressures. The presence of the subjectoxygen-dentated ligands permits such a substantial reduction in thecarbon monoxide partial pressure of the reaction system that 1 bothhydroformylation and hydrogenation can be accomplished in a singlereactor and/ or with but a single catalyst system.

By an oxygen-dentated chelation ligand as used herein is meant anorganic compound containing at least two oxygen atoms, each of which isbonded to a ditferent carbon atom, and wherein these two oxygen atomsare separated by at least two and less than five intermediate atoms ofthe compound. I

In the active form, the suitable stabilized cobalt carbonyl catalystswill contain most of the cobalt component in a reduced valence state.This will usually be a zero valence state, and possibly may even be a 1valence state.

As used herein, the term complex compound relates to combinations of twoor more atoms, ions, or molecules which arise as a result of theformation of a bond(s) by the sharing of a pair(s) of electronsoriginally associated with only one of the components, and thecomplexpossesses some identifiable physical or chemical character-Organic compounds in general which contain at least one pair of oxygenatoms and have the aforementioned configuration are suitable ligands forthe stabilization of cobalt carbonyl complex compounds provided that theligand exihibits a substantial standard cobalt-ligand associationconstant and is free of interfering substituent groups. In general, bestresults obtain where the ligandstabilized cobalt carbonyl complexcompound is soluble in the reaction system.

By a standard cobalt-ligand association constant as used herein is meantthe constant at 18-30 C. in a solution containing at least 25 weightpercent of water for the equilibrium:

where L is the ligand, a is the charge (0,l,1) value of the ligand andwhere the balance of the solvent is a nonchelating organicoxygen-containing solvent.

By a substantial cobalt-ligand association constant is meant a value forlog K (units are liter molas follows:

(1) for a wholly aqueous solvent a value of at least 4 (2) for a 75-25dioxane-water medium a value of at least (3) for a 75-25 acetone-watermedium a value of at least about 7.

For representative data and background information see StabilityConstants of Meal-Ion Complexes by L. G. Sillen and A. E. Martell,Special Publication No. 17, London; The Chemical Society, BurlingtonHouse, 1964.

Cobalt carbonyl complex compounds which are free of cobalt phosphorusbonds and of cobalt-metal bonds, other than cobalt-cobalt bonds, are ingeneral stabilized by the method of the instant invention. Especiallyadvantageous is the use of the present method for the stabilization ofdicobalt octacarbonyl, cobalt hydrocarbonyl, and tetracobaltdodecacarbonyl, i.e., cobalt complex compounds and the systems tendingto equilibrate which result where mixtures of these materials and carbonmonoxide gas are at temperatures in the range from about 100 C. to about225 C.

The cobalt-containing complexes which are stabilized by the instantmethod can be prepared by known methods. In this preparation, thesubject oxygen-dentated ligands may be present during the generation ofthe cobalt carbonyl complex compound or subsequent thereto. In general,best results in terms of stabilization effects obtain when these ligandsare present initially. Normally these complexes are formed in situ bythe reaction of cobalt oxide, a cobalt salt or soap with hydrogen andcarbon monoxide at elevated temperatures and pressures in a reaction inwhich a mixed species of carbonyls appear to be formed includingdicobalt octacarbonyl, cobalt hydrocarbonyl and a cobalt salt, Co[Co(CO)The mixture tends to equilibrate as between these species and at a lowerrate, in the absence of the subject ligands, with cobalt metal. Themechanism of the present stabilization may actually be a kinetichindrance of the latter stage. The medium for the in situ preparation ingeneral comprises a liquid reactant, for example an unsaturated organiccompound or an olefinic hydrocarbon, from a reaction system for whichthe cobalt carbonyl complex is to serve as a catalyst. Inert liquidmedia or diluents such as saturated hydrocarbons, aromatic hydrocarbons,alcohols, high boiling reaction by-products, etc. as known in the artmay also be employed.

The amount of the subject oxygen-dentated ligands which should bepresent for satisfactory results varies and in general appears to befunctionally related to the cobaltligand association constant. That is,for a given stabilization (time-temperature and corresponding degree ofcobalt metal formation) a smaller amount of a ligand having a highassociation constant will be required for satisfactory stabilizationthan of a ligand having a relatively lower association constant.Oxygen-dentated chelation ligands satisfactory for use in the presentinvention should have a cobalt-ligand association constant, watermedium, of at least about 10 liter mol or, 75-25 dioxane-water medium ofat least about 10 liter molor corresponding values for otherwater-non-chelating organic solvent media. In general, the stabilizingeffect increases as the association constant becomes larger.

The relative amount of the added oxygen-dentated ligand which should bepresent varies. Usually even a trace, i.e., of the order of 10* mols peratomic weight of cobalt, is helpful. However, as a practical matter, ingen-' eral at least about 0.001 mol of the ligand per atomic weight ofcobalt in the cobalt carbonyl complex compound should be added. Goodresults are usually experienced when for each atomic weight of cobaltthere is present in the system an amount of the ligand in the range 0.05to 0.5 mol. Larger amounts of added ligand may be desirable where theligand has a relatively small association constant. For example, in thecase of salicylaldehyde as much as 2 mols of the aldehyde per atomicweight of cobalt is a useful ratio, whereas for a ligand such assalicyclic acid (K-5 10 only one-quarter to one-half as much ligandshould be present. Usually, better results obtain when the ratio issubstantially less than stoichiometric, i.e., is in the range 0.1-0.25to 1.

Organic compounds containing the aforedescribed bidentate functionalgrouping, i.e., the two oxygen atoms plus the associated intermediateatoms, having a substantial cobalt-ligand association constant and freeof interfering groups, are useful in the practice of the instantinvention. Thus, within the contemplated scope of the invention arecompounds of all structural variations compatible with the presence ofthe above bidentate functional group.

Representative structural-types include acyclic, cyclic polycyclic,heterocyclic and mixed structural variations thereof.

The electron pair donor atoms of the ligand, the oxygen atom pair, maybe present in any carbon-oxygen functional group. Representativecarbon-oxygen functional groups include carbonyl, carboxyl, ester,ether, aldehyde, and the like groups.

The carbon skeleton of the ligand compound may be saturated, partiallysaturated, aromatic and mixtures there- Preferably, the oxygen-dentatedligands used in the practice of the invention are composed of carbon,hydrogen and oxygen, and preferably are soluble in the reaction system.The ligand may, however, contain one or more non-interfering functionalgroups substituted for one or more hydrogen atoms attached to carbonatoms which are not included in the bidentate functional grouping, i.e.,the two oxygen atoms which together with the intermediate atoms of thecompound and a cobalt atom can form a heterocyclic chelate ring.

By non-interfering substituent groups, as used herein, is meant -SO -R(R is hydrogen or a hydrocarbyl group); non-chelating (i.e., locatedoutside of the bidentate functional grouping, as defined above)hydroxyl, carboxyl, ether, ester, keto, or aldehydes functional group;nonchelating nitrogen groups as amino, imino, nitrilo, and amide groups;and halogen groups as fluoride, bromide, and chloride.

Representative oxygen-dentated ligands useful in the practice of thisinvention include salicylic acid, 4-ethyl salicylic acidsalicylaldehyde, 4-methoxysalicylaldehyde, catechol,3-hydroxy-2-methyl-4-pyrone, kojic acid, tropolone, a-methyl-tropolone,,B-methyltropolone, a-isopropyltropolone, fl-isopropyltropolone,2,4-pentanedione, hexane-2,4-dione, 3-methylpentane-2,4-dione,S-methylhex- 5-bromo-salicylaldehyde,6,7-dihydroxynaphthalene-2-sulfonic acid,1,1,l-trifiuoro-l-naphthoylacetone.

In particular, ligands of the formula AR(CQ R) (OR) (R),,, in which the(OR) and (CO R) groups, relative to each other, are in the ortho or1,2-geometrical relationship, are preferred for use as stabilizers inthe present. invention. AR of the formula is an aromatic hydrocarbonnucleus containing less than aromatic carbocyclic carbon atoms, the Rgroups of the formula may be the same or different groups and arehydrogen or an alkyl group having a carbon atom content in the range1"to 50 and n is the balance of the extra-carbocyclic valences of thearomatic ring, i.e., 4 for the benzene ring, 6 for naphsatisfactoryherein. For example, in olefin hydroformylation, suitable reactiontemperatures are in the range 100- 225 0., preferably from about 125 toabout 200 C. Suitable catalyst-to-feed ratios may vary widely andpreferably are varied to achieve, where possible, a substantiallyhomogenous reaction mixture. Catalyst concentra tions, based upon olefinfeed (weight percentages) and calculatedas cobalt metal in the range0.05 to 5.0 weight percent are usually satisfactory. Preferred amountsordinarily are in the range 0.1 to 0.5.

At elevated temperatures, cobalt carbonyl compounds are normallymaintained as carbonyls by subjecting them to substantial partialpressures of carbon monoxide. These pressures may be satisfactorilyemployed in the instant invention, but in general the stabilizing actionof the subject oxygen-dentated ligands markedly lowers the partialpressure of carbon monoxide required for this purpose. Thus, for thepresent process, system pressures may vary from about 50 p.s.i.g. attemperatures of the order of 75 C. up to as much as 4000-6000 p.s.i.g.at temperatures of the order of 225 C. The advantages of the instantinvention are optimal at the relatively moderate pressures of the rangefrom about 100 to 2 000 p.s.i.g.

The ratio of hydrogen to carbon monoxide charged may vary widely withinthe scope of the invention. Usually, a mol ratio of hydrogen to carbonmonoxide in the thalene, 10 for biphenyl, etc. The effect of thearomatic nucleus of this class of compounds appears in general toenhance the cobalt-ligand association constants relative to thealiphatic-type ligands and to thus provide a better stabilizationefiect.

The ligands of the tropolone group are also preferred. These compoundsare semi-aromatic, if not actually aromatic, in character and they, too,exhibit substantial.

cobalt-ligand association constants. They are of the formula hydrogen oran alkyl group having a carbon atom content in the range 1 to 50 and nis 5.

In accordance with the invention and in particular aspect thereofalcohols and/ or aldehydes are prepared by in which the R groups are thesame or different and are the hydroformylation of olefinic compounds byintimately contacting them in the liquid phase with hydrogen and carbonmonoxide in a reaction catalyzed by complex cobalt carbonyl compoundsand stabilized by the presence of added oxygen-dentated ligands at welldefined conditions of temperature and pressure.

The principal effect of the presence of oxygen-dentated ligands of theinvention upon cobalt carbonyl. complex compounds is that of inhibitingtheir destructive dissociation with the formation of cobalt metal..Little or no. interference with the normal catalytic action of cobaltcarbonyl compounds occurs from the presence of the added ligands. Thus,in general, in the employment of the stabilized cobalt carbonyls of theinvention the conditions which are satisfactory asknown inthe art aralso olefins of the C to C range, propylene oligomers and the like, arethe more desirable feeds. Where branched chain olefins are used for theproduction of oxo-alcohols, it is often more advantageous to effect thecarbon monoxide-hydrogen addition to the olefinic double bond at about-170 C. and to subsequently heat the reaction mixture to a highertemperature (-210" C.) where the reduction of the aldehyde groupproceeds more favorably.

Representative olefinic hydrocarbons suitable for use herein includeethene, propene, l-hexene, cyclohexene, betapinene, alpha-pinene,2-heptene, 3-ethylpentene-l, 2- methylpentene-2, cyclopentene,di-isobutylene, propylene trimer, codimer heptenes, vinylcyclohexene,cyclododecene, 3-eicosene, l-dodecene and the like olefinichydrocarbons.

Cobalt Carbonyl Stability Test The stabilizing action of oxygen-dentatedligands upon complex cobalt carbonyl compounds is shown by means of asuitable test. The relative stabilizing action of oxygendentated ligandsupon these carbonyl compounds is shown by subjecting them to a standardset of conditions with and without the added ligand. These conditionsinclude:

Temperature, C 190.

Time, hrs. 6.

Solvent Mixed alcohol-alkane. H :CO mol ratio 2:1.

Pressure, p.s.i.g 1600-1800.

W ith 0.236 grams of cobalt as octanoate in 50 g. n-heptane-l- 50 g.C12C1s 0x0 alcohol.

The test is carried out in a stainless steel rocking autoclave having aglass liner. Under these conditions cobalt salts such as cobaltZ-ethylhexanoate are rapidly converted to complex cobalt carbonyls.Therefore, as a matter of convenience, the salt rather than the carbonylcompound is charged to the autoclave. After the six hours at temperaturewith agitation, the autoclave and contents is cooled to room temperatureand vented. The solution is then filtered and analyzed for cobaltcarbonyl by infrared absorption at 2041 CHI-"1. Metallic solid ifpresent and tem surfaces.

its form is noted. In the absence of stabilizers and under the foregoingconditions all of the cobalt carbonyl is converted to a cobalt metalplate which is found adhering to TABLE II the walls of the glass linerand autoclave. In the presence gagg of an effective stabilizer, littleor no metal plating-out oc- 5 Ligand curs, or but small amounts offilterable metal powder are Hydroformylation type Colwwfloml Stabilizedformed. With stabilizers of intermediate effectiveness, lit- Exam 7 3 l9 tle or no metal is found in the liner; but metal is found g g 175 200190 outside the liner, either deposited on the external liner pressu'io,js'i 5.1: 3,500 4,400 2,200 Carbon monoxide. 1, 550 3, 000 700 wall orthe autoclave wall, or loosely lodged between the 10 Hydrogennn '85 1400 1' 400 liner and the autoclave wall. Decomposmons outside the Time,min 180 10s liner appear to be due to the higher temperatures which (2)exist at the autoclave wall because of the proximity of theIIII.IIIIIIIIIIIIIIII-II heating element and the low level of thestabilizer. The 82 85 88 stabilizer inhibits decomposition of the cobaltcarbonyl l s 12 e in the solution inside the liner, but does not preventsome 16 12 diffusion through the vent holes in the liner into the voidTropolone ligand used at ratio oil mol per mol Co between the liner andthe autoclave inner wall. In Table needed- 1 below is listed a number ofrepresentative test results.

TABLE I Ligand used Wt. Cobalt as Ligandpercent Mols C02 (CO)s cobalt ofsoluper mol percent of association No. Type tion cobalt cobalt tedconstant Observations 1 None None Mainly metal plated inside liner wal 2Salicylic acid 0.14 0.25 43 5x10 N0 metal, Co(CO) presen 3Tetrapropenylsuccinic 0. 1 0. 08 16 -10 Some metal powder in acid.liner. 4 Acetylacetone 2 l 0 2X105 Metal powder but no plating-out. 5Salicylaldehyde 0. 05 2 14 5x10 Do. 6 l,4-di hydroxyanthra- 0.05 0. 05 0Metal plate outside liner.

quinone.

1 All runs with 0.236 grams of cobalt as octanoate in 50 g.n-heptane-i-50 g. 012-0 0x0 alcohol.

I Pyridine added to promote cobalt carbonyl formation. 8 Trace wateradded-no adverse effect.

4 Where oxo alcohol omitted from solvent, cobalt carbonyl remains fullystable in presence of acetylacetone.

The foregoing examples illustrate that oxygen-dentated ligands areadvantageous for the stabilization of complex cobalt carbonyl compounds.In the absence of these stabilizers, in order for there to be areasonable stabilization of cobalt carbonyls, there must be a carbonmonoxide partial pressure of about 2500 p.s.i.g. at 190 C. In the aboveexamples the carbon monoxide partial pressure was only 530600 p.s.i.g.Thus, the presence of the stabilizers permit large reductions in thecarbon monoxide partial pressure.

Even where the stabilizing action of the ligand was not sufficient tomaintain at least some cobalt carbonyl values in the system after sixhours of the severe test conditions, nevertheless the presence of theligands (example 4) has a salutory effect. Ordinarily reaction times areless than six hours and stabilizers such as acetylacetone andsalicylaldehyde and the like are actually effective for these periods.In addition, the loss of stabilization activity by these materialsappears to be due to their reducibility. Thus at lower reactiontemperature where hydrogenation is not favored and where aldehydeproducts predominate, these stabilizers are more effective. A furtheradvantage resulting from the use of the oxygen-dentate ligands asdemonstrated by the examples is that such cobalt metal as is produced isin the form of a loose metal powder rather than as an adheringplated-out film upon the raction sys- Examples 7-9 Advantages of theinstant process are illustrated by comparative examples in which C -Ca-olefin feeds are converted to oxo alcohols in a cobalt carbonylcatalyzed hydroformylation using commercial catalyst requirements, e.g.,0.2-0.35 weight percent of cobalt based upon olefin and otherconditions, as noted as follows:

From the above examples it is seen that in the absence of thestabilizing oxygen-dentated ligands of the invention more process stagesand/or more severe operating pressures and longer reaction times arerequired for the hydroformylation of alkenes to alcohols. Thus, inexample 7, two process stages were required for the production ofalcohol. In addition, a decobalting step between the hydroformylationand hydrogenation is necessary. Also, a separate hydrogenation catalystrequirement is involved. On the other hand, in a conventional singlestage hydroformylation to alcohol as in example 8, inconvenient andextremely high operating pressures are necessary. In general, equipmentcosts and operating costs are seriously increased by such highoperational pressure requirements. As shown in example 9, the process ofthe present invention permits the use of substantially lower pressuresand a single stage process for the production of alcohol from olefinsand hydrogen costs are less because synthesis gas rather than purehydrogen can be employed.

These data indicate that the subject ligands do not change the nature ofthe effective cobalt carbonyl catalyst species in a hydroformylation. Itfurther appears that the action of these ligands in facilitating ahydroformylation reaction is in the nature of inhibiting cobalt metalformation. Cobalt carbonyl catalyzed hydrogenations of 0x0 aldehydes arefavored by high temperatures (200 C.) and by low pressures of carbonmonoxide. Thus, the presence of the instant ligands permits operationunder conditions which permit effective conversion of olefins toalcohols in a single stage and in good yields.

Examples 10-1 8 In these runs a C alpha olefin feed was hydroformylatedin a stirred autoclave under the conditions noted in Table III belowwith the results as noted.

TABLE III Stability of cobalt catalyst in oxo runs effects ofacetylacetone and of carbon monoxide preteatment Acetylacetone Cobaltmoles/mole cobalt Initial gas Reaction conditions 4 Wt., Added Pres-Percent as sure, Temp., H2200 Pres, Time Example of olefin Source 1Hacac 2 Total Type p.s.i.g. 0. Ratio p.s.i.g. hours Cobalt as metal 0.68 C(O0t)z 0 0 C0 500 193 2:1 1,500 2 All, plated out. 0. 68 Co(Oct) 2 2CO 500 193 2:1 1,500 2 None. 0.46 Co(acac)z 0 2 Ha-l-CO 1,500 193 2:11,500 2 All, loose powder. 0.46 Co(acac)1 0 2 Hz+00 2, 200 193 2:1 ,2002 None. 0. 46 Co(acac) 4 6 H1+CO 2, 060 193 2:1 2, 060 2 All, loosepowder. 0. 46 00(3080): 4, 6 CO 500 193 2:1 2,140 2 None. 0. 92 Co(acac)0 2 CO 500 190 1.521 1,400 2 Do. 0.39 Co(aoac)a 0 2 CO 250 151 2:1 1,125 12 Do. 0.39 Co(acac)z 0v 2 CO 700 210 1.7:1 2, 560 2 Do.

l Cobalt sources: C0(OCt)g is Cobalt octoate (2-ethylhexoate); Co(acac)9is acetylacetone derivative of Cobalt.

2 Hacac is acetylacetone.

8 Initial gas added at reaction temperature in these runs. Added at roomtemperature in other runs 4 All runs in glass liner with 25 g. C13alpha-olefin and 75 g. n-heptane.

In the absence of an oxygen-dentate ligand, acetylacetone, in run 10,all of the cobalt metal plated out. Under the same conditions as run 10except that a ligand is added, run '11, none of the cobalt isconvertedto metal, and there is an effective stabilization.

Where both hydrogen and carbon monoxide are present initially in theformation of the cobalt carbonyl complex compound, runs 12, 13 and 14, ahigh conventional carbon monoxide pressure, run 13, is necessary toprevent cobalt metal deposition. On the other hand, where the cobaltcarbonyl is prepared in the absence of hydrogen, muns 15-18, and thenemployed in a hydroformylation, there is an effective stabilization ofthe cobalt. It appears that acetylacetonate (acetylacetone ligandprecursor) is easily reducible during formation of the cobalt carbonylcatalyst from cobalt acetylacetonate and carbon monoxide. Hence, in runs12, 1'3 and 14 little or no stabilizing ligand is available and all ofthe cobalt is reduced to metal except where the carbon monoxide pressureis sufficiently high.

Examples 19-36 In these runs a C alpha olefin feed was hydroformylatedin a stirred autoclave under the variety of conditions and usingoxygen-dentated ligand catalyst stabilizers as noted in Table IV below.The product composition and other data were as indicated.

In addition to the variety of oxygen-dentate ligands demonstrated, theabove examples 19-36 show advantages: (1) for the staging oftemperature, a lower firststage oxonation followed by a higherhydrogenation temperature; (2) for the use of lower relative amounts ofligand where the ligand associates strongly, kojic acid for example; and(3) for the use of higher hydrogen to carbon monoxide mol ratios.

The standard cobalt-ligand association constants for all of the ligandsin these demonstrations were in the range above about 10 water medium,or 10 dioxane-water medium. These examples establish thatoxygen-dentated ligands of the invention are useful and efiectivestabilizers for complex cobalt carbonyl compounds. They also demonstratethat where some destructive dissociation of complex cobalt compoundsinto cobalt metal is unavoidable or even desirable, as in a decobaltingstep in an oxo process, the subject oxygen-dentated ligands inhibit theplatingout of the thus-formed cobalt metal on the surfaces of reactorvessels, lines, etc.

I claim:

1. In the reaction of a C C olefinically unsaturated hydrocarbon withcarbon monoxide and hydrogen wherein the reaction is catalyzed by acobalt carbonyl complex compound, which is free of cobalt-phosphorusbonds and of metal-metal bonds other than cobalt-cobalt bonds, the

TABLE IV. -OXO REACTIONS MODIFIED BY DIKETONES Catalyst 3 Ligand CobaltMoles Conditions 1 Time, min. First Products, mole percent wt., per halfpercent mole Temp., Pres., After life, Alde- Thick Example of olefinType cobalt C. p.s.i.g. Induct. induct. min. Alcohol hyde Parafiin oil0. 68- Acetylacetone 2 182-196 1, 500 0 150 -10 86 Trace 10 4. 3 0.46-..do 2 182-195 2, 200 0 120 6 81 Trace 11 7. 8 0.47 PhCOCH2CO s 2188-201 2,075 14 120 4 3 (80) Trace 3 (9) 5 (11) 0. 47 Ph-C OCHz-C O-Ph.2 190-201 2, 080 10 120 4 a (78) Trace 5 (9) 3 (13) 0. 47 (CH3OCaH -CO)zCHa 2 189-200 2, 110 10 120 8 80 Trace 11 9 0. 49 01 2 188 2, 150 18155 5 (21. 3) 5 (58.2) (7) a (10) 1 190 2, 200 5 108 6 81 Trace 6. 6 120, 2 190 1,516 120 120 0 10. 8 0 0, 1 190 2, 125 0 130 30 6. 2 7

Effects of temperature 0. 39 Acetylacetone 2 210 2, 560 0 120 81 Trace12 6. 4 0. 39 -do 2 171 1. 775 20 136 3 a (5. 4) 3 (6) 0. 39 ..-do 2 1511, 125 80 750 30 78 0. 5 5. 7 16 0. 47 Ethyl acetoacetate 2 2, 100 "00-133 "10:1o 78 Trace 7 18 0.47 Acetylacetoue 0- 5 2. 1g 8 (19) a (28) a(3) 0. 38 .....do 2 190 290 a0 no e1 Trace 4. 4 1s. 5

Effects of Hg: CO ratio 34 0.38 Hacae (4:1 H1200) 2 2,025 30 31118 10 673 8 22 a5 o. 92 Hacac (41 In; 00) 2 177 2, -10 7s Trace e. 4 15 as o. 92Hacac (5:1 H1200) 2 i: 53 5 40 a5 Trace 4. 5 9.8

1 All runs with 75 g. n-he tane, 25 g. C13 alpha-olefin; except asnoted, 2:1 Hz: CO.

2 Catalyst formed from obalt -2 ethylhexoate, except for runs withacetylacetone cobalt of 2 1.

4 Hacac is acetylacetone. Metal formed in Examples 35 and 36.

i Cobalt salts converted cobalt carbonyl at higher temperature beforeadding olefin.

improvement which comprises carrying out the reaction at a temperaturein the range from 75 C. to 225 C. and about 50 to 5000 p.s.i.g. and withthe reactants in contact with from 0.001 to 1 mole per gram of cobalt ofan.

oxygen-dentated chelation ligand of the formula ized in that for eachatomic weight of cobalt there is present an amount of the ligand in therange from about 0.05 to about 0.5 mol.

4. The improvement as in Claim 1 further characterized in that for eachatomic weight of cobalt there is present an amount of the ligand in therange from about 0.1 to 0.25 mol.

5. The improvement as in Claim 1 further characterized in that theligand is tropolone.

6. The improvement as in Claim 1 furthercharacterized in that saidligand is present while said complex compound is produced by thereaction of carbon monoxide and a .cobalt. salt or oxide and in theabsence of added hydrogen gas.

7. The improvement as in Claim 1 further characterized in that theunsaturated compound is a mono-olefinic hydrocarbon.

8. In the reaction of a C C alpha olefin with carbon monoxide andhydrogen catalyzed by a cobalt carbonyl complex compound which is freeof cobalt phosphorus bonds and of metal-metal bonds other thancobalt-cobalt bonds,'the improvement which comprises effecting thereaction at a temperature of about C. and a pressure below about 2200p.s.i.g. and wherein for each atomic weight of cobalt there is about 1mol of tropolone present.

References Cited UNITED STATES PATENTS 3,274,263 9/1966 Greene et al.260632 HF 3,488,296 1/1970 Senn et al 260632 HF 3,454,649 7/ 1969 Cullet a1. 260-638 HF 3,576,881 4/1971 Senn 260632 HF 3,594,425 7/1971Brader et a1. 260632 HF 2,576,113 11/1951 Hagemeyer 260-638 HF 2,641,6136/1953 Mertzweiller et al... 260638 HF 3,404,188 10/1968 Privette et al.260638 HF JOSEPH E. EVANS, Primary Examiner US. Cl. X.R.

260-4482 E, 598, 604 HF, 617 HF, 631.5, 638 HF, 683.65

1. IN THE REACTION OF A C2-C20 OLEFINICALLY UNSATURATED HYDROCARBON WITHCARBON OONOXIDE AND HYDROGEN WHEREIN THE REACTION IS CATALYZED BY ACOBALT CARBONYL COMPLEX COMPOUND, WHICH IS FREE OF COBALT-PHOSPHORUSBONDS AND OF METAL-METAL BONDS OTHER THAN COBALT-COBALT BONDS, THEIMPROVEMENT WHICH COMPRISES CARRYING OUT THE REACTION AT A TEMPERATUREIN THE RANGE FROM 75*C. TO 225*C. AND ABOUT 50 TO 5000 P.S.I.G. AND WITHTHE REACTANTS IN CONTACT WITH FROM 0.001 TO 1 MOLE PER GRAM OF COBALT OFAN OXYGEN-DENTATED CHELATION LIGNAD OF THE FORMULA